Table of Contents

Introduction

Why Unity? Low Barriers to Entry

MonoDevelop: Built-In Code Editor for Unity

Visual Studio Community 2015

Cost of Unity

Building a VIrtual Environment

Scenes

GameObjects

Components

Prefabs

Unity UI

Important Unity Dev Classes

MonoBehaviour

Transform

RigidBody

Networking

Built-in Pieces

Network Behavior

Client/Server Communication

Common Pitfalls

Pitfalls Filled In

What's Missing?

Future Implementations

Unity vs. Unreal

Introduction

• Unity is a game engine developed by Unity Technologies
• The application has many uses from building games and creating virtual environment
• Unity supports many different platforms like: PC, Mac, Linux, Android, iOS, PS4, Xbox One, Wii U, Webgl and more

Why Unity? Low Barriers to Entry

• There's a lare community marketplace
  • with lots of cool free assets
  • and lots of high quality assets
• It's built on familiar languages
  • UnitScript (Javascript)
  • C#
• Huge Development Library
  • Physics
  • Networking
  • UI
  • Audio
• Comes with Free Dev Tools

Screen Shot 2016-03-05 at 1.22.02 PM.png

MonoDevelop: Built-In Code Editor for Unity

• Unity comes with a code editor called MonoDevelop that syncs with your projects
• This means you can launch MonoDevelop independently of your Unity application, but not have to worry about updating/syncing anything
• If you prefer another code editor you can configure Unity to launch that, instead of MonoDevelop (Visual Studios)

MonoDev_StartUp.png

Visual Studio Community 2015

Cost of Unity

• Free personal edition and pricey professional edition
• Current licensing rate for indie devleopers or small studios is $75/month
• Source code available for undisclosed price
• Professional edition offers discounts in marketplace, analytic tools and team licensing

Building a VIrtual Environment

• Unity can be used to build both 2D and 3D environments
• 3D games built on X, Y, Z coordinate system
• Z+ being forward, X+ to the right and Y+ up

Scenes

• Scenes contain the objects of your game
• Can be anything from a menu to a level in your game
• We build our game environments in scenes

GameObjects

• Every object in your game is a gameobject
• Can be anything from a building, to individual walls, crates, barrels, camera, trees and even the player itself
• Each object has special properties like its position, scale, texture, and more
• we call these properties components

Components

• Components are functional pieces of a gameobject
• Components contain key information like Transform, meshes, physics, scripts, audio, network, etc.

List of active components of a gameobject

Prefabs

• Users store gameobject with all of its components into prefabs (prefabricated object)
• Contributes to convenience and reusability of a project

Unity UI

Important Unity Dev Classes

• MonoBehaviour
  • standard functions and events that get triggered during gameplay interaction
• Transform
  • information regarding position, rotation, and scale, for a given game object
  • provides the necessary functions to manipulate that information
• RigidBody
  • provides properties and functions that handle velocity, force, ass, torque, collision, and other physics-related stuff

MonoBehaviour

• is the base class that every script in Unity derives from. By inheriting the behavior of this class, the scripts that the developer creates can access the "inner workings" of Unity

• Update - the function that handles the frame update of the script/object
  • often used for movement, triggering events, and responding to input
  • relies on connections and variables that are created in Start function
• Start - the function that is calledbefore Update is called for first time
  • used for initialization of variables within the script

Ex_C#_Script.png

Transform

• Everyobject in a scene has a Transform
• used to store and manipulate the position, rotation and scale of the object
• Every Transform can have a parent, which allows you to apply position, rotation and scale hierarchically

Screen Shot 2016-03-07 at 8.22.57 PM.png

RigidBody

• Adding a RIgidBody component to an object will put its motion under the control of Unity's physics engine
• The RigidBody class lets you apply forces to the object and control it in a physically realistic way

Networking

• Interpolation
• Client-side prediction
  • De-Sync
  • Lockstep
• Client-Authoritative
• Local player, client, server, and host

Built-in Pieces

• Network Manager allows you to easily configure the server and networking aspects of your game
  • Online/Offline scene
  • IP/Port
  • Player Spawning
  • Spawnable Prefabs

Network Behavior

Extends MonoBehaviour, and must be used whenever you need to work with networking within the script

• Creating objects
• Moving objects
• Producing changes to the world

Enables:

• Client/server checks
• running code only on the client or servers

Client/Server Communication

SyncVar: Change on server -> update clients


Command: Run this code only on server


ClientCallback: Run t his code only on client



Spawning:

• instantiating an object onlycreatese the object in the "local" world
• must use NetworkServer.Spawn to put the bullet on server/clients

Common Pitfalls

Cameras

• should only be one active camera at a time
• multiplayer can mess this up

Control Scripts

• Remote clients will still receive local input if the script is active

Audio Listener

• You only want one of these active - local player most likely

Pitfalls Filled In

Camera:

• Deactivate scene-wide
• activate the local player's camera

Control Scripts:

• Enable if local player, deactivate otherwise

AudioListener:

• Enable if local player, deactivate otherwise

What's Missing?

General Opinion: Built-In options are not suitable for games with a large number of players

• Hard to control the built-in components, generally just write your own

Physics:

• Networking physics is a nightmare
  • Requires Client-Side tracking of the last ~2 seconds of past states and input
  • Client-SIde prediction cannot predict movement accurately because of non-deterministic physics -> noticeable inaccuracies in all but the best of systems
  • Server authoritative system can cause huge amounts of recalculation
  • Very nuanced and susceptible to bugs

Future Implementations

Chat Box

• Being able to have scrollable chat box on the bottom of the screen that all players can communicate with within the server
• Plenty of legally usable code on line to create, the GUI and communication between different players

Login Menu

• Creating a login menu, probably storing different accounts with username and passwords in a database

Unity vs. Unreal

• Quicker start up compared to Unreal
• Quicker to set a prototype
• Once you start stretching limits you hit walls on Unity (physics, networking)
• Some people make Unity then port it into Unreal
• Unity's animation system is much easier to use than Unreal